LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Jens Wiklander <jens.wiklander@linaro.org>
To: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org,
	linux-doc@vger.kernel.org
Cc: Jerome Forissier <jerome@forissier.org>,
	Etienne Carriere <etienne.carriere@linaro.org>,
	Sumit Garg <sumit.garg@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Jens Wiklander <jens.wiklander@linaro.org>
Subject: [PATCH v5 1/6] docs: staging/tee.rst: add a section on OP-TEE notifications
Date: Thu, 26 Aug 2021 14:30:27 +0200	[thread overview]
Message-ID: <20210826123032.1732926-2-jens.wiklander@linaro.org> (raw)
In-Reply-To: <20210826123032.1732926-1-jens.wiklander@linaro.org>

Adds a section on notifications used by OP-TEE, synchronous and
asynchronous.

Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 Documentation/staging/tee.rst | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst
index 4d4b5f889603..3c63d8dcd61e 100644
--- a/Documentation/staging/tee.rst
+++ b/Documentation/staging/tee.rst
@@ -184,6 +184,36 @@ order to support device enumeration. In other words, OP-TEE driver invokes this
 application to retrieve a list of Trusted Applications which can be registered
 as devices on the TEE bus.
 
+OP-TEE notifications
+--------------------
+
+There are two kinds of notifications that secure world can use to make
+normal world aware of some event.
+
+1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION``
+   using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter.
+2. Asynchronous notifications delivered with a combination of a non-secure
+   edge-triggered interrupt and a fast call from the non-secure interrupt
+   handler.
+
+Synchronous notifications are limited by depending on RPC for delivery,
+this is only usable when secure world is entered with a yielding call via
+``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure
+world interrupt handlers.
+
+An asynchronous notification is delivered via a non-secure edge-triggered
+interrupt to an interrupt handler registered in the OP-TEE driver. The
+actual notification value are retrieved with the fast call
+``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. Note that one interrupt can represent
+multiple notifications.
+
+One notification value ``OPTEE_SMC_ASYNC_NOTIF_VALUE_DO_BOTTOM_HALF`` has a
+special meaning. When this value is received it means that normal world is
+supposed to make a yielding call ``OPTEE_MSG_CMD_DO_BOTTOM_HALF``. This
+call is done from the thread assisting the interrupt handler. This is a
+building block for OP-TEE OS in secure world to implement the top half and
+bottom half style of device drivers.
+
 AMD-TEE driver
 ==============
 
-- 
2.31.1


  reply	other threads:[~2021-08-26 12:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 12:30 [PATCH v5 0/6] Asynchronous notifications from secure world Jens Wiklander
2021-08-26 12:30 ` Jens Wiklander [this message]
2021-08-26 12:30 ` [PATCH v5 2/6] dt-bindings: arm: optee: add interrupt property Jens Wiklander
2021-08-26 12:30 ` [PATCH v5 3/6] tee: fix put order in teedev_close_context() Jens Wiklander
2021-08-26 12:30 ` [PATCH v5 4/6] tee: add tee_dev_open_helper() primitive Jens Wiklander
2021-08-27  6:23   ` Sumit Garg
2021-08-27  9:26     ` Jens Wiklander
2021-08-26 12:30 ` [PATCH v5 5/6] optee: separate notification functions Jens Wiklander
2021-08-26 12:30 ` [PATCH v5 6/6] optee: add asynchronous notifications Jens Wiklander

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210826123032.1732926-2-jens.wiklander@linaro.org \
    --to=jens.wiklander@linaro.org \
    --cc=ardb@kernel.org \
    --cc=corbet@lwn.net \
    --cc=devicetree@vger.kernel.org \
    --cc=etienne.carriere@linaro.org \
    --cc=jerome@forissier.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=op-tee@lists.trustedfirmware.org \
    --cc=robh+dt@kernel.org \
    --cc=sumit.garg@linaro.org \
    --cc=vincent.guittot@linaro.org \
    --subject='Re: [PATCH v5 1/6] docs: staging/tee.rst: add a section on OP-TEE notifications' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).